#include<stdio.h>

int main()
{
 	int n,i;
 	printf("please enter a integer number,n=?");
 	scanf("%d",&n);
 	for(i=2;i<n;i++)
 		if(n%i==0) break;
 	if(i<n) printf("%d is not a prime number.\n",n);
 	else printf("%d is a prime number.\n",n);
 	return 0;
}

